How to redirect the stdin and stdout of child process which exec interactive prog?

john.daker · 11-04-2008, 03:55 AM

Hi all

I have a program which has four processes:
father process: get the standard input from user
child process 1: exec `bc`(for example)
child process 2: exec `ftp`
child process 3: exec `ssh`

How can I send the input from father process to all the three processes as their stdin , and got the output of the 3 processes return to father process rather then print to stdout?

Thanks

ta0kira · 11-04-2008, 09:27 AM

You need to use pipe and dup2. pipe will create a set of pipe descriptors and dup2 can move those over old file descriptors, in this case being standard input and standard output.
ta0kira